Friday, 26 February 2010

You Can With a Yacon

It seems like another piece of received wisdom about Andean root crops must now be decapitated and left for dead in a ditch: that viable yacon seeds are hard to produce and hard to germinate. I used to subscribe to this view - until last Monday in fact. No longer. Like these newly emerging yacon seedlings, I've seen the light.

Speaking botanically, these seedlings issued forth from achenes - hard, dry fruits, looking like mini versions of black sunflower "seeds", to which they are structurally very similar. You may also see the term cypselae used to describe these non-juicy fruits. We'll let the botanists tussle over the validity of one versus the other - they're pretty much identical.

The yacon-sunflower similarity doesn't stop at the seeds - sorry - achenes. The flowers, as shown here, betray their common ancestry: both belong in the daisy family, the Asteraceae. Yacon's blooms are a shy, retiring version of the sunflower's in-your-face boldness, which seems strange, given its prodigious vegetative performance.

Anyway, I was a bit dubious about these seeds when they arrived in one of Frank van Keirsbilck's regular (and irresistible) parcels of horticultural temptation last autumn; he's the devil in disguise.... They had a certain dusty, funereal aura about them and I duly forgot all about their existence until around two weeks ago. Then, during a febrile bout of rationalisation, I rediscovered them. Grow or go, I thought as I tossed them onto some moist paper towel to imbibe.

The latter seemed more likely when they became totally covered in thick mould growth less than a week after sowing. But hold on - peering through the fungal fog, I noticed, with something akin to disbelief, that several of them were actually germinating. Result!

I claim no credit whatsoever in this success, other than the fact that I finally found the necessary motivation to actually sow them. They came from Frank's plants in Belgium and are the result of crosses between some of his varieties. Just like with oca, it appears that if you've got the right combination of varieties, seed production isn't that difficult to achieve. It will be interesting to see how they turn out, if I can get them through those awkward first few weeks of life. To the uninitiated, all seedlings look the same. We know different. Prepare to stifle those yawns when I accost you with the regulation boring baby snaps in due course.

Quite exciting! Did Frank say how he got the seed to set? I get plenty of mature flowers on my yacon, and was thinking of trying eating the buds next year, but now I will look out for seed - unless you tell me that it's necessary to have four different varieties, cross pollinated in a specific order by a certain species of hummingbird on the day of the winter solstice. This would not surprise me after reading your posts on oca pollination. Some plants will do anything to avoid inbreeding.

Owen,not every seed came from crosses, although I could have send you only the ones that came from crosses. I do have some true seeds from the New Zealand variety, and possibly some of 'morado' as well. It seems that these two purple-skinned varieties set seeds easier. I had the feeling that the seeds were viable, some of them were obviously empty, but some just had 'the right touch and thickness'. It could be interesting to work further with easy seed-setting varieties, that way some more diversity could be created. By the way, you were earlier, I still have to start sowing my yacon seeds, I have plenty left. I just wonder where to place all these plants...?

If you are looking for information on plants, I found an interesting site that seems to have collated lots of pdf files (journal articles and other grey literature) relating to edible plants including Apios americana, and Amphicarpaea bracteata. You might find it interesting.

Catofstripes - thanks, but it's probably best if you hold on to those tuberous pea seeds for now - I've got to lavish a serious amount of love on the yacon babes and probably won't be able to protect them (Lathyrus) from the slugs this season. But I'm determined to grow them again - they're delicious (10,000,000 slugs at my plot can't be wrong).

IAP - don't know about the hummingbirds, or the effects of chanting om whilst walking backwards around the plants whilst waving smudge sticks etc, but the main difficulty is that the female flowers and male flowers mature at different times- the ray flowers are female and mature first, the disk ones are male (so I guess that makes them protogynous). Bumblebees are supposed to be effective pollinators.

Frank - the ones that you sent were the cross of the morado with the New Zealand variety. I agree that we should be working to get more diversity into these crops. It seems like you're already doing a splendid job on that front! If we can master the seed biology, then breeding or selecting for shorter season plants, tuber taste and quality will be possible and the crop can become better adapted to our climate and latitude. I suspect that some of the seeds display dormancy, which is common in daisy family plants - see how yours go. Did you pollinate them by hand or did you allow the insects to do it?

Mark - I've just had a look and you're absolutely right, it is interesting. There's a few old favourites that I recognise and plenty that I don't - nice to have them all together like that. Thanks for your offer of congratulations, which, like I said, really belongs to Frank.

The main interest in mentioning the fungi site is that they can supply lots of mycorrhizae for inoculation of seedlings. One might imagine that it could possibly reduce the horror of Damping Off zapping ones seedlings.Plus the Stropharia rugoso-annulatus would make short work of composting also giving delicious mushrooms.

Owen, these were hand-pollinated. Some other ones, which I suspect will be true-to-type weren't hand-pollinated. The varieties that flowered early grew separately, I suspect some 35-40 metres between the varieties and lots of natural barriers, including some big fruit trees (cherry, apple, pear). So I really think these didn't cross. The New ZEaland variety seems to be promising, that was the one that set seeds quite abundantly. Unfortunately only the morado flowered at the same time, the other ones flowered later (or not, as was the case of a Peruvian variety), I tried to cross in some of the 'common' yacon ( brown-skinned tubers) with the NZ yacon, but autumn was already quite close and these seeds didn't ripen off. I also think there was some weather stress last year (dryness) which made them flower earlier.

About Me

I'm a botanist and horticulturist with a longstanding interest in edible and useful plants. I founded an alternative seed company called Future Foods and I also worked in the Heritage Seed Library at Ryton Gardens, HDRA, growing heirloom vegetables for distribution to the members. I'm the only person I know who has tried to grow Japanese knotweed and failed.
Other interests include walking, cycling, music and natural history.